GCSE Flashcards
Why is it important to control body temperature?
so enzymes work their best
chemical reactions are at their fastest
to prevent damage to enzymes/cells
Reflex action vs action controlled by hormones
- reflex action quicker
- effect of reflex action over shorter period
- hormone involves blood system and reflex involves neurones / nerve cells
ignore nervous system / nerves - reflex involves impulses and hormone involves chemicals
- reflex action affects only one part of the body
Why can insulin not be taken as a tablet?
insulin is a hormone - which is a type of protein - which get broken down in the stomach during digestion
What are hormones?
they are chemical messengers sent in the blood produced by a gland
Describe how the mature eggs are used in IVF treatment so that the woman may become pregnant.
egg is fertilised using a male sperm
this forms an embryo
embryo inserted in woman’s uterus
Why have IVF clinics have been set a target to reduce multiple births?
multiple births lead to low birth weight
multiple births can cause harm to mother (miscarriages)
Which microscope is used for what?
- light microscope - lets us see the nuclei - lower resolution
- electron microscope - lets us see mitochondria, ribosomes, plasmids and chloroplasts - higher resolution + magnification so gives a sharper image
Why can antibiotics not treat viruses?
viruses live inside cells
Colonies of bacteria are formed through:
cell division
Repeats help to check the…
reliability
Uses of stem cells:
- medical research
- medical treatment
What happens in a red blood cell?
oxygen combines with haemoglobin
Why does glucose concentration first increase then decrease in the small intestine?
carbohydrates are broken down into sugars by amylase
What is starch a type of?
carbohydrate
What is amylase a type of?
carbohydrase (which is an enzyme)
Why does concentration of glucose in the small intestine decrease?
absorption of glucose
into the blood
by active transport
Osmosis
- The movement of water molecules from a high concentration to a low concentration through a partially permeable membrane.
- It is a passive process
What happens if cell is put into water?
water moves in
cell will swell
cell may burst
Roots absorb
water and mineral ions
If a plant loses water..
it wilts or dies
Adaptions of the lung for gas exchange:
many alveoli
short diffusion pathway (one cell thick)
large SA
good blood supply (steep concentration gradient)
Parts of a plant
- permanent vacuole contains cell sap (weak concentration of sugars + salts)
- chloroplast contain chlorophyll (green pigment) that absorbs light, and is the site of photosynthesis
- rigid cell wall - contains cellulose which strengthens and supports the cell
If it asks to circle the egg cell in a punnet square, what do you circle?
one X chromosome under the mother
If it asks to circle the sperm cell in a punnet square, what do you circle?
one Y chromosome under the father